She doesn't know how to eat healthy, that's what the OP wants to TEACH her.

Even if you don't get to choose what to buy (although most parents know what their kids like and that's what they buy), she can choose her portion sizes and decide how much of what she wants to eat. These are all skills that must be taught

I think it's a great idea to do if you hear her mention something about dieting or weight loss. If not, can you speak to someone she is close to and see if you can get them concerned for her? Maybe helping the concerned friend/relative/other close person will have an effect. At least you can walk away knowing you gave it your best shot.

How about showing her photos from when you were heavy?

Don't specifically make it about your weight, though. Do it as sharing family memories and there just happens to be pics of you heavy. Point out that it's you, and when she says something along the lines of, "you look so different!" that can be your opening?

One of the best ways of teaching is modeling. Don't say a word to her about weight unless she or someone else brings up your weight. Then you can say, "Thanks! I found this great site blah blah blah." Be open that you are going to exercise and that you enjoy it as me time.

If no one mentions weight, bring it up yourself about YOU. "Remember when I had (random medical problem)? My doctor said since losing weight, it's all cleared up. If only had someone told me that watching my portions could do so much! I wish I had believed in myself enough to start this sooner." (Or whatever.)

you're not getting my point. teaching her what to do will have little effect if someone else is buying her food.

for instance i was lucky enough to grow up with a family who believed in whole foods, but i also knew kids who's parents bought crap like lunchables, hot dogs, etc. the only veggies were frozen french fries. the only fruit is what was in strawberry ice cream. they ate tons of mcdonalds and pizza, etc.

sorry but if you're trying to lose weight and are obese, there is no healthy portion size of hot dog, ketchup ramen, mrs paul fish sticks, ice cream etc if that's all you're given to eat

sure the OP can teach her how to combine her meals, make healthy salads with baked chicken or salmon, but what if this girl's parents aren't buying food like that? kids dont exist in a bubble

Assuming the guardians would absolutely never change what they buy no matter how she begs them, eating 1 instead of 2, or learning what the portion sizes ARE and how to read the ingredients on a package and learning what nutrients she should try to get is all important and can take her a long way on her journey.

Im really shocked that the grandparents just let her sit there and eat that many cookies and ice cream in a sitting =x!!

I think the majority of her problem is she isnt being provided with the right food and she gets away with eating badly and I hate to say it but the grandparents are the main reason as to why she is big as she is still a child and needs someone to take control of her actions a bit more.

I think your best off addressing them first and once that's been done then chat with your niece. Like many other people have said I wouldn't mention her weight as most people who are big or overweight already know they are and don't need telling again and again and again. I think mentioning your story would be a great way to show her what a fab role model you are, she probably would notice your weight loss and ask you before u even tried mentioning it to her.

I do hope this young girl gets some good help, whether it be from you or her grandparents, i wish I could have had the help when I was younger :) good luck :D

You mentioned that your sister has lost a good bit of weight as well. If she's going to be there at the same time talk to her about weight loss in front of your niece. Trade tips, experiences, recipes, etc. Your niece will hear it and be able to join the conversation and ask questions if she wants to but it won't be so direct. If you just start talking to her about her weight she'll just get defensive and shut down.

Chiming in that this is a terrible idea and there is absolutely no way to bring this up to the girl without coming off as cruel and mean-spirited. If SHE mentions it to YOU, there's an open door to gently talk about how you improved your own eating habits etc. When I was about 13 my grandparents stopped by to visit for the first time in several years, "gently" told me I was too fat, and sailed away on a cruise. That in no way helped me and I can't imagine how an adult she hardly sees stopping by on vacation to tell her that she's fat will inspire her to do anything other than cut you out of her life.

Talk to the grandparents about buying her cookies and ice cream. Do not confront the girl.

I've switched just about everything in our house without telling my two young kids (7&4) to all natural products( I.E. natural jiff peanut butter the ingredients are peanut butter and palm oil) Having a diabetic grandfather I use to eat and snack with him growing up which was pretty bland when it came to ingredients in taste so I knew my biggest challenge was keeping them wanting to eat healthy. Our household in my opinion would rank at the 7.5 or 8 out of 10 for the health factor when it comes to food and the kids eat really wellm here's how we did it. Starting with my 4 year old, he would wake up all hours of the night , be hyper etc. Most people called it being a kid but my wife and I knew it was his diet. We went though the cupboards and ditched anything that had preservatives and or sugary. Product number one was Nutella! You might as well be feeding your kids cotton candy with this stuff. Instead of sugar we use stevia in the raw which is a plant that is 300% more sweeter than sugar but has zero calories, does not effect the glucose spiking our kids blood sugar making it safe for diabetics as well. We took the stevia and baked cookies, cakes, fresh squeezed lemonade. We also created a shelf in the fridge thats strictly for the kids, if they want a snack they can help themselves as much as they want from that shelf only. On that shelf is string cheese, yogurts lots of fruit pre-peeled and cut up if needed. This takes all the thinking out of "what should I eat" for them. So although the foods that they eat may seem like the sugary stuff they like, there is in fact no sugar in them which allows their pancreas to stay steady with the insulin production keeping them from going crazy candy freaks then crashing into naps which messes up their sleep patterns causing them to wake me up through the night

I think one issue a lot of overweight kids have is that they feel uncomfortable with their bodies and they end up not liking sport/working out/gym because of it. I think this happens with girls a lot (I'm sure guys too I just don't really know any teenage boys haha) because of puberty etc.

If you maybe tried to find a non-competative sport or activity she liked, maybe that would help encourage her to become active. Maybe going for a walk each night and trying to get further and further each time? Maybe setting up a geocaching/scavenger hunt?
When I was younger I loved horse back riding because I could do it by myself. Another good option would be if she could get a "job" walking someone's dog. A couple bucks a week and she could walk it everyday after school or something. Even giving her a gift like an cheap mp3 player and making her a playlist of your favourite work out songs (or a CD if she already has an mp3 player) so she can dance in the privacy of her own room could help her develop confidence and a love of movement. Creating something shared and special between you two might help her feel more comfortable about talking to you too.

It's tough because no matter what kind of progress you make while you're there, it's up to the rest of her family to keep it going. And it sounds like they aren't super motivated like you are.

I was a year younger when my auntie had this discussion with me. Offered a weight I should be, offered hints and tips. My auntie is one of my best friends, then and now. I cried myself to sleep that night.

OP all you are going to achieve is hurting your niece even more. You are not close to her, see her once a year and you don't like her. You're doing this out of obligation not out of care. The advice to get to know you niece is the best. Find something you like about her. This girl already has enough issues without you adding to them. I assure you she's aware of her weight. Talk to the people who can change it your parents. Suggest councelling if it's possible.

I applaud you and wish more parents were like this. I get that parenting is tough - and I get that it's a whole new battle once kids are school aged and influenced by outside forces, but I hate when I see little kids walking around with bags of chips or candy or just eating junk in general. At early ages there is no one responsible for their food but you (with occassional exceptions). I saw a woman on the bus recently repeatedly giving her kid Starbursts. The kid couldn't have been more than 3 and in the 10 minute bus ride had eaten 3 Starbursts, which the mother clearly bought and provided for her. It's just so unnecessary. You get a few scant years to completely control diet and influence their choices, why in the hell would you introduce that junk? And I know for some people they just don't know any better. I just wish more people knew better.

i dont pity her....i want her to be healthy...just because i dont enjoy being around her does not mean i dont want what is best for her....if there was nothing to love about this "poor child" i would have said screw it let her get bigger..BUT i'm not, i want to help her...seriously why do you think i asked for help with this....i'm pretty surprised by some of the replies but i guess that is what happens when you ask for opinions....no worries, i will work with her when i go home and i will work with my parents (her grandparents) and i will do what i can....that is all anyone can do....denise

thank you very much...well said and pretty much what i think i'm going to do....

it does have to do with her grandparents who she lives with and if you read other things that i have replied to on this post I AM GOING to have a talk with them as well...my stepmom will be far more help than my dad who is clueless and honestly not a great role model....my step mom is just overwhelmed with having another child to raise after her 2 grew up and as sad as it is to say has pretty much just given up so my niece is suffering because of lack of interest. i want them all to change and make better choices but i am primarily concerned with chelsie and that is what i am going to work on while i'm there.....

^^^^^^^^
THIS.